Cospas-sarsat beacon tester in a removable expansion card for a handheld computing device

ABSTRACT

A remote tester for a radio frequency beacon includes a plug-in module insertable into a cooperating slot in a handheld computing device so as to communicate data between the module and the computing device, wherein the module includes an antenna, at least one radio frequency receiver cooperating with the antenna so as to receive radio frequency signals from the beacon, a processor cooperating with the receiver, and a host interface for coupling in the slot with the computing device for data interchange between the processor in the module and a processor in the computing device.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional PatentApplication No. 60/611,738 filed Sep. 22, 2004 entitled Cospas-SarsatBeacon Tester.

FIELD OF THE INVENTION

This invention relates to the field of plug-in peripheral applicationmodules for use in handheld computing devices such as so-called personaldigital assistants, and in particular to such an application plug-incard or module for use in remotely testing data from a radio frequencybeacon.

BACKGROUND OF THE INVENTION

Cospas-Sarsat is a satellite system designed to provide distress alertand location data to assist search and rescue (SAR) operations, usingspacecraft and ground facilities to detect and locate the signals ofdistress beacons operating on 406 Megahertz (MHz), 121.5 MHz or 243 MHz.An important feature of 406 MHz emergency beacons is the addition of adigitally encoded message, which provides such information as thecountry of beacon registration and the identification of the vessel oraircraft in distress, and optionally, position data from onboardnavigation equipment. An auxiliary transmitter (121.5 MHz or 243 MHz) isusually included in the 406 MHz beacon to enable suitably equipped SARforces to home on the distress beacon. To ensure that 406 MHz beaconsare compatible with the Cospas-Sarsat System, detailed specificationsand type approval testing standards have been adopted. Periodic testingof the Cospas-Sarsat beacons is required to ensure functionality of thebeacons and to indicate whether these devices still meet the requirementstandards of Cospas-Sarsat. Consequently, it would be desirable, and itis an object of the present invention to provide, a portable handhelddevice for testing of such beacons, and in particular a plug-in card ormodule or the like (collectively alternatively referred to herein as amodule) for use with a handheld computing device (HCD) such as apersonal digital assistant (PDA) for such testing.

As noted by Mills et al. in U.S. Pat. No. 6,353,870 which issued Mar. 5,2002, a problem in the prior art, and one which is purportedly addressedby Mills et al., is the limited capabilities for expansion orcustomization, a PDA being provided with at most one or two slots forremovable expansion cards for input/output (I/O), I/O adapters, memoriesand memory adapters including expansion cards having DRAM, SRAM, ROM,Flash technologies. It is noted that I/O expansion cards also haveincluded dedicated peripherals, networking, modems, wirelesscommunications, serial I/O, and bar-code and other scanners.

Also in the prior art of which applicant is aware, U.S. Pat. No.5,671,374 which issued Sep. 23, 1997 to Postman et al. discloses the useof a PDA or similar host equipped with PC card interfaces for I/Odevices including portable laser scanners, magnetic stripe and inkreaders, key boards and key pads, OCR devices, and track balls. Postmanet al. introduce the abstract to their specification by stating that avariety of PC card interfaces interface from many different types ofinput devices to PDAs or palm-top computers through PCMCIA slots so thatthe PDAs receive data from barcode scanning engines, and so as to decodethe data and pass the decoded data to the PDA via PCMCIA pin bus.Applicant is also aware of U.S. Pat. No. 6,842,652 which issued Jan. 11,2005, to Yeung which discloses a camera or image capture deviceinsertable into an expansion slot of a handheld PC or PDA.

Also in the prior art, applicant is aware of U.S. Pat. No. 5,519,577which issued May 21, 1996 to Dudas et al. wherein embodiments are taughtfor a PC card-based radio for applications based in a portable host sothat, as taught by Dudas et al., when used with a local area networkinstalled within a facility, a scanner or other device may communicatedirectly with a computer that manages inventory in the facility, theexample given of using a spread spectrum radio for use in a portablebarcode scanner.

What is neither taught nor suggested, and what it is one object of thepresent invention to provide, is the mounting of a radio frequencyreceiver into an insertable housing shaped to conform with the formfactor for a plug-in peripheral card or module for use with a HCD suchas a PDA, wherein the receiver section is left protruding from the HCDfor two-way radio communication from an exposed end of the plug-in cardor module. The opposite plug-in end of the card or module is releasablymounted in co-operating communication with the processor within the HCD.

Applicant is also aware of U.S. Pat. No. 6,289,464 which issued Sep. 11,2001 to Wecker et al. as describing a system and method for receivingwireless information on a portable computing device which includespowering the wireless receiver of the device only from a battery of theportable computing device. The device receives wireless information andstores the wireless information in the memory of the wireless receiver.It is neither taught nor suggested, and is an object of the presentinvention to also provide, without intending to be limiting, a radiofrequency antenna, RF radio and interface controller mounted within thehousing of the plug-in card or module so as to be substantially enclosedwithin the body of the wherein the processing of the informationreceived remotely from a beacon through the beacon tester plug-in moduleaccording to the present invention, is tested and specified parametersdecoded so as to be graphically displayed on the display of the HCD.

SUMMARY OF THE INVENTION

In summary, the present invention may be characterized in one aspect asa remote tester for a radio frequency beacon, wherein the testerincludes a plug-in module insertable into a cooperating slot in ahandheld computing device so as to communicate data between the moduleand the computing device, and wherein the module includes an antenna, atleast one radio frequency receiver cooperating with the antenna so as toreceive radio frequency signals from the beacon, a module processormounted in the module and cooperating with the at least one receiver soas to process data from the at least one receiver, a host interface forcoupling in the slot with the computing device for data interchangebetween the processor in the module and a module processor in thecomputing device. One or both processors include means such asprogrammed software applications resident and operating in theprocessors for analyzing the data. The at least one receiver may includea 406 MHz receiver, and a 121.5 MHz receiver, or a 243 MHz receiver.

In one embodiment the module has a first end and an opposite second endinsertable into the slot so as to leave the first end of the moduleexposed when the module is mounted in the slot. Advantageously, theantenna is mounted in the first end of the module.

The means for analyzing the data may include means for, and in acorresponding method according to the present invention the steps of:computing frequency and/or frequency stability from the data, decoding aCospas-Sarsat protocol from the data, computing power from the data,computing modulation symmetry from the data, decoding Morse code fromthe data, listening to demodulated audio from the data, and/or computinga spectral analysis from the data. The module may further comprise ameans for receiving an external clock reference signal, or a means forreceiving the radio frequency signals from the beacon by way of anelectrically conductive conduit mountable into radio frequencycommunication with the at least one receiver in the module.

A method according to another aspect of the present invention ofremotely testing a radio frequency beacon comprising the steps of:

-   -   a) providing a plug-in module comprising a beacon tester card        for mounting in data communicating interface within a        cooperating slot in a handheld computing device, wherein the        card includes an antenna, at least one radio frequency receiver        cooperating with the antenna so as to receive radio frequency        signals from the beacon, a module processor cooperating with the        at least one radio frequency receiver, a host interface for        coupling in the slot with the computing device for data        interchange between the module processor and a processor in the        computing device,    -   b) configuring the handheld computing device so that both the        processor and memory resident in the handheld computing device        and a display of the handheld computing device will process data        from the module and store and display the results of processing        of the data so as to indicate values for specified parameters        allowing for assessment of the functioning of the beacon,    -   c) insertably mounting the module into the slot so as to        interface, for data communication between, the host interface        and the processor, and so as to provide power to the module from        the computing device,    -   d) bringing the module and the handheld computing device into        within a radio frequency receiving range proximal to the beacon,    -   e) detecting and receiving in the module radio frequency signals        emitted by the beacon,    -   f) transmitting data corresponding to the received signals from        the module via the host interface to the processor of the        handheld computing device,    -   g) computing from the data at least the values of the specified        parameters for evaluation of the functioning of the beacon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is, in perspective view, a plug-in module according to thepresent invention mounted into the expansion slot of a PDA.

FIG. 2 is, in front elevation view, the plug-in module and PDA of FIG. 1illustrating information received from a Cospas-Sarsat beacon beingtested.

FIG. 3 is, in left side bottom view, the plug-in module of FIG. 1 beinginserted into the expansion slot of the PDA.

FIG. 4 is the view of FIG. 3 with the resilient caps on the exposed endof the plug-in module opened to provide access to the input ports.

FIG. 4 a is, in right side top perspective view, the plug-in module ofFIG. 4 being inserted into the expansion slot of the PDA.

FIG. 5 is a block diagrammatic of the arrangement of antenna, receiversection and host interface within the plug-in module according to thepresent invention.

FIG. 6 is a block schematic representation of the signal processingwithin the plug-in module in the beacon tester according to the presentinvention.

FIG. 7 is, a sample beacon test report illustrating a display of powerversus time, spectrum, and phase versus time representative of theresults of testing of a Cospas-Sarsat beacon using the beacon testeraccording to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As used herein, it is understood that reference to a Compact Flash™ isnot intended to be limiting, but is intended to include other removableexpansion card form factors or other application plug-in modulesaccommodating the space requirements and interface characteristics ofthe acceptable form factors for mounting of the application plug-inmodules, memory cards, expansion cards, and other peripheral interfaceplug-in devices (collectively and alternatively referred to herein asplug-in modules) into the openings, apertures, expansion slots or thelike (collectively alternatively referred to herein as slots) providedin HCDs or other portable computing devices including PDAs hereincollectively and alternatively referred to as either HCDs, host devicesor host computing devices.

Thus what is provided in the plug-in module according to the presentinvention is a beacon tester card for mounting in communication with thehost computing device using a plug-in module inserted into an expansioncard slot, so that the auxiliary functions unique to the beacon testerare found within the plug-in module, and the processing, display andmemory functions, etc. are of the host computing device.

Although the Cospas-Sarsat authority and regulations regulate andcontrol the 406 MHz band for use in beacons, it has not heretofore beena straight-forward exercise to use a single portable small handheldcomputing device to test the 406 MHz and auxiliary homing frequency of121 MHz and the 243 MHz frequencies as employed by a beacon. In thepresent invention, the plug-in module provides for analysis of bothpower and frequency including in some embodiments frequency stability onall such three frequencies, namely, 406, 121, and 243 MHz. In addition,in a preferred embodiment, the beacon tester according to the presentinvention measures wave form characteristics of all three receivedfrequencies and may in addition measure the following parameters, whichare not intended to be limiting:

The Cospas-Sarsat C/S T.007 annex J Beacon Quality Assurance Planrequires frequency stability measurements. The device according to thepresent invention is illustrated in FIGS. 1–4, wherein correspondingreference numerals denote corresponding parts in each view. In usebeacon testing module 10 is mounted into the expansion slot 12 in HCD14, which in illustration is a PDA such as a Dell X50. In use, module 10is inserted into slot 12 in HCD 14 in direction C. A user of the devicemay in one embodiment provide a stable 10 MHz frequency reference signalby plugging in a suitable mating connector (not shown) into the 10 MHzreference input located under the right hand resilient cap 18illustrated in front perspective view in FIGS. 4 and 4 a. For use in anon-wireless application, an external coaxial cable input port 20 islocated on the opposite side of module 10 to the 10 MHz reference input16, and similarly is located under a corresponding resilient cap 22 soas to provide for direct radio frequency input. An internal antenna 24is mounted within the exposed end 10 a of the plug-in module 10 andprovides for 406 MHz reception remote from a beacon (not shown) beingtested.

As seen in FIG. 5, and in better detail in FIG. 6, module 10 containsinternal antenna 24 within the exposed end 10 a. A switch 26 allows auser to switch between the use of antenna 24 and external input 20 forreceiving the radio frequency signal from the beacon being tested. Thesignal from the beacon is communicated to a receiver section 28 which inthe embodiment of FIG. 6 comprise 406 MHz receiver 28 a, 121.5 MHzreceiver 28 b, and 243 MHz receiver 28 c. Switch 30 provides forselecting the signal from the corresponding receiver for feeding toprocessor 32. A clock signal 34 is provided to an analog to digitalconverter (ADC). As stated above, an external 10 MHz reference signalmay also be provided by external reference input 16 to processor 32. Thereceiver section 28 and processor section 32 are enclosed within module10 and the data then passing via host interface 36 into the HCD 14.Module 10 thereby takes advantage of the computing capabilities residentwithin the HCD.

In a preferred embodiment, in embodiments of the present inventionproviding for frequency stability measurements, a delimited text file isproduced for input into a spreadsheet, database, graph or documentwithin the application software operating within HCD 14. The processingsoftware decodes Cospas-Sarsat protocols on Cospas-Sarsat frequencychannel allocations, within the 406 MHz to 406.1 MHz band. Thus thedetailed parameters set out in Tables A and B and FIG. 7 are measuredand may be converted to corresponding graphic displays which may bedisplayed on HCD display 14 a, and such as seen by way of example in theTest Report of FIG. 7, and in particular which show, respectively,examples of 406 MHz phase modulation (Phase vs. Time), 406 MHz power(Power vs. Time) during a burst beacon transmission so as to check forany battery problems, and a 406 MHz in-band spectrum (spectrum) so as toprovide a virtual spectrum analyser to check for spectral maskviolations.

In embodiments testing for frequency stability, measurements may includea burst count, a average repetition rate, the frequency detected, thenominal frequency value, the short term, the mean slope, the residualfrequency, and the test duration time. Connecting the external 10 MHzfrequency reference provides for a very accurate frequency measurement.

In one embodiment, the internal antenna 24 mounted within the plug-inmodule 10 receives the transmitting beacon signal within a range of upto ten meters (for 406 MHz), or again, a direct input connection forexample by using a coaxial cable connecter, allows for measurementdirectly from the output of a screen box or 5 Watts (W) directly fromthe beacon. The application software automatically saves the measureddata within the memory and retrieval system (not shown) incorporatedinto the HCD and may create a file such as an HTML file for printing atest report on a remote or networked printer.

Although the application cited herein is that of 406, 121.5, 243 MHzfrequency applications, those are not intended to be limiting as it isintended to be within the scope of the present invention to provide formeasuring other frequencies used in emergency locating beacons.

In a preferred embodiment, the present invention provides for real-timeaudio on 121.5 MHz or 243 MHz frequencies and a further preferredembodiment may also decode Morse code.

As will be apparent to those skilled in the art in the light of theforegoing disclosure, many alterations and modifications are possible inthe practice of this invention without departing from the spirit orscope thereof. Accordingly, the scope of the invention is to beconstrued in accordance with the substance defined by the followingclaims.

TABLE A 406 MHz 121 MHz 243 MHz Measure all Cospas- Frequency FrequencySarsat frequency channels Decode all Cospas-Sarsat Peak power Peak powerprotocols Display UIN and full Sweep Direction Sweep Direction HEXFrequency Audio Frequency Audio Frequency Frequency stability SweepRange Sweep Range Power Duty Cycle Duty Cycle Power Rise Time ModulationFactor Modulation Factor Phase Modulation Sweep Repetition Rate SweepRepetition Rate Modulation Symmetry Listen to Demodulated Listen toDemodulated Audio Audio Modulation Bit Rate Decode Morse Code DecodeMorse Code CW Preamble

TABLE B Accuracy Parameter provided: 406 MHz Measurements Measure allCospas-Sarsat Frequency Channels Decode all Cospas-Sarsat Protocols 15HEX ID & Full HEX Frequency (using INT REF) (resolution = 100 Hz)Leaving Factory ±100 Hz Long Term ±0.4 ppm/year Frequency (using EXTREF) (resolution = 1 Hz) ±1 Hz Frequency - Nominal Frequency ±2.5 ×10⁻¹¹ Stability Short Term Medium Term - Mean Slope Medium Term -Residual Power ±1 dB Power Rise Time ±0.5 ms Phase Modulation ±0.04 radModulation Rise and Fall Times ±10 μs Modulation Symmetry ±0.005Modulation Bit Rate ±0.2 bps CW Preamble ±0.8 ms 121.5/243 MHzMeasurements Frequency (using INT REF) (resolution = 100 Hz) LeavingFactory ±100 Hz Long Term ±0.4 ppm/year 121.5 Frequency (using EXT REF)(resolution = 1 Hz) ±30 Hz 243 Frequency (using EXT REF) (resolution = 1Hz) ±30 Hz 121.5 Peak Power ±1.5 dB 243 Peak Power ±1.5 dB SweepDirection — Audio Frequency ±30 Hz Duty Cycle ±2% Modulation Factor ±5%Sweep Repetition Rate ±0.1 Hz Graphic 406 Power screen Graphic 406 PhaseModulation screen Graphic 406 In-Band Spectrum screen MiscellaneousRange (using Internal Antenna): 406 MHz >10 m 121.5 MHz >3 m RF InputVSWR 1.10:1 RF Input Level: 406 MHz Burst −13 dBm Min +40 dBm Max 121.5MHz −28 dBm Min +31 dBm Max 10 MHz REF Input VSWR 1.15:1 10 MHz REFInput Level −10 dBm Min +10 dBm Max Operating Temperature Range 0° C. to+50° C. Storage Temperature Range −20° C. to +60° C. InternalTemperature Sensor Accuracy ±0.5° C. RF Input Cable TerminationBNC-female 10 MHz REF Cable Termination SMA-female Dimensions: w × l × hmm (inches) 43.5 (1.71) × 58.5 (2.30) × 12.7 (0.50) in PDA w × l × h mm(inches) 73 (2.87) × 140 (5.50) × 16.5 (0.65) *User must supply a stable10 MHz Reference Signal

1. A remote tester for a radio frequency beacon, the tester comprising:a plug-in module insertable into a cooperating slot in a handheldcomputing device so as to communicate data between said module and saidcomputing device, wherein said module includes an antenna, at least oneradio frequency receiver cooperating with said antenna so as to receiveradio frequency signals from the beacon, a module processor mounted insaid module and cooperating with said at least one receiver so as toprocess data from said at least one receiver, a host interface forcoupling in said slot with said computing device for data interchangebetween said processor in said module and a module processor in saidcomputing device.
 2. The device of claim 1 wherein said module has afirst end and an opposite second end insertable into said slot so as toleave said first end of said module exposed when said module is mountedin said slot.
 3. The device of claim 2 wherein said antenna is mountedin said first end of said module.
 4. The device of claim 2 wherein saidat least one receiver includes a 406 MHz receiver.
 5. The device ofclaim 2 wherein said at least one receiver includes a 121.5 MHzreceiver.
 6. The device of claim 2 wherein said at least one receiverincludes a 243 MHz receiver.
 7. The device of claim 1 further comprisingmeans for analyzing said data.
 8. The device of claim 7 wherein saidmeans for analyzing includes means for computing frequency from saiddata.
 9. The device of claim 7 wherein said means for analyzing includesmeans for computing frequency stability from said data.
 10. The deviceof claim 7 wherein said means for analyzing includes means for decodinga Cospas-Sarsat protocol from said data.
 11. The device of claim 7wherein said means for analyzing includes means for computing power fromsaid data.
 12. The device of claim 7 wherein said means for analyzingincludes means for computing phase modulation from said data.
 13. Thedevice of claim 7 wherein said means for analyzing includes means forcomputing modulation symmetry from said data.
 14. The device of claim 7wherein said means for analyzing includes means for decoding Morse codefrom said data.
 15. The device of claim 7 wherein said means foranalyzing includes means for listening to demodulated audio from saiddata.
 16. The device of claim 7 wherein said means for analyzingincludes means for computing a spectral analysis from said data.
 17. Thedevice of claim 1 wherein said module further comprises a means forreceiving an external clock reference signal.
 18. The device of claim 1wherein said module further comprises a means for receiving the radiofrequency signals from the beacon by way of an electrically conductiveconduit mountable into radio frequency communication with said at leastone receiver in said module.
 19. A method of remotely testing a radiofrequency beacon comprising the steps of: a) providing a plug-in modulecomprising a beacon tester card for mounting in data communicatinginterface within a cooperating slot in a handheld computing device,wherein said card includes an antenna, at least one radio frequencyreceiver cooperating with said antenna so as to receive radio frequencysignals from the beacon, a module processor cooperating with said atleast one radio frequency receiver, a host interface for coupling insaid slot with said computing device for data interchange between saidmodule processor and a processor in said computing device, b)configuring said handheld computing device so that both said processorand memory resident in said handheld computing device and a display ofsaid handheld computing device will process data from said module andstore and display the results of processing of the data so as toindicate values for specified parameters allowing for assessment of thefunctioning of the beacon, c) insertably mounting said module into saidslot so as to interface, for data communication between, said hostinterface and said processor, and so as to provide power to said modulefrom said computing device, d) bringing said module and said handheldcomputing device into within a radio frequency receiving range proximalto the beacon, e) detecting and receiving in said module radio frequencysignals emitted by the beacon, f) transmitting data corresponding to thereceived signals from the module via the host interface to the processorof the handheld computing device, g) computing from the data at leastthe values of the specified parameters for evaluation of the functioningof the beacon.
 20. The method of claim 19 further comprising the step ofcomputing frequency from said data.
 21. The method of claim 19 furthercomprising the step of computing frequency stability from said data. 22.The method of claim 19 further comprising the step of decoding aCospas-Sarsat protocol from said data.
 23. The method of claim 19further comprising the step of computing power from said data.
 24. Themethod of claim 19 further comprising the step of computing phasemodulation from said data.
 25. The method of claim 19 further comprisingthe step of computing modulation symmetry from said data.
 26. The methodof claim 19 further comprising the step of decoding Morse code from saiddata.
 27. The method of claim 19 further comprising the step oflistening to demodulated audio from said data.
 28. The method of claim19 further comprising the step of computing a spectral analysis fromsaid data.